Electrical switch having angularly oriented rectangular contacts

ABSTRACT

An electrical switch in which pairs of fixed contacts are mounted in the switch body which supports a rotor carrying a roller contact for each pair of fixed contacts. Each of the fixed contacts is disposed at an acute angle to a line extending from a pivot axis of the rotor through that contact so that the portion of the surface of the roller which engages a fixed contact moves axially along the roller as the roller is moved angularly over the contact.

v United States Patent [191 [111 3,718,794 Tregurtha [451 Feb. 27, 1973 [54] ELECTRICAL SWITCH HAVING [56] References Cited ANGULARLY ORIENTED UNITED STATES PATENTS RECTANGULAR CONTACTS 983,414 2/1911 Watkmson et a1 ..200/166 BB 2,629,787 2/1953 Coies ct al. ..200/11 K [75] Inventor: Steven John Tregurtha, Oswaldtwis- FOREIGN PATENTS OR APPLICATIONS tle, England 767,769 9/1967 Canada ..200/61.28

[73] Assignee: iIBoseph lllsucas (Industries) Limited, Primary Examiner Herman Hohauser England Assistant ExaminerM. Ginsburg [22] Filed: M r h 1, 1972 Attorney-John C. Holman et a1.

[21] Appl. No.: 230,624 [57] ABSTRACT An electrical switch in which pairs of fixed contacts are mounted in the switch body which supports a rotor carrying a roller contact for each pair of fixed con- [30] Foreign Application Priority Data tacts. Each of the fixed contacts is disposed at an acute angle to a line extending from a pivot axis of the March 5, 1971 Great Bntam ..6,217/71 rotor through that Contact so that the portion of the surface of the roller which engages a fixed contact [52] "200/166 200/11 200/6127 moves axially along the roller as the roller is moved [51] Int. Cl. ..H01h 9/00 angular), over the Contact. [58] Field of Search ZOO/166 B, 11 J,

ZOO/61.27, 166 BH, 200/11 K, 61.28

4 Claims, 4 Drawing Figures ELECTRICAL SWITCH HAVING ANGULARLY ORIENTED RECTANGULAR CONTACTS This invention relates to electrical switches.

An electrical switch, according to the invention includes a body, a rotor mounted for pivotal movement relative to the body, a roller carried by the rotor and defining a movable contact of the switch, resilient means urging the roller into engagement with the body, and a pair of contact blades carried by the body, each contact blade being of rectangular cross section and being arranged so that one axial end surface of the respective contact blades is positioned in the path of movement of the roller, the contact blades defining fixed contacts of the switch and the roller bridging the fixed contacts to complete a circuit therebetween in one angular position of the rotor, at least one of the contact blades being arranged so that one edge of said one axial end surface of the contact blade is inclined at an acute angle to a line extending radially from the pivot axis of the rotor through said contact blade so that the portion of the surface of the roller which engages said one axial end surface of the contact blade moves axially along the roller as the roller is moved angularly over said one axial end surface.

Conveniently, the axis of rotation of the roller is inclined at an acute angle to an imaginary line passing through the pivot axis of the rotor and the center of gravity of the roller so that during angular movement of the roller over said contact blades the surface of the roller undergoes sliding movement as well as rotational movement relative to the contact blades and hence provides a cleaning action to the contact blades.

In the accompanying drawings, which illustrate one example of the invention,

FIG. 1 is a sectional side view of an electrical switch,

FIG. 2 is a plan view of FIG. 1 with parts thereof removed from the sake of calrity,

FIG. 3 is a diagrammatic illustration in plan view of the switch shown in FIG. 1, and

FIG. 4 is a diagrammatic illustration in plan view of a modified arrangement to that shown in FIG. 3.

Referring to the drawings, the switch includes a moulded synthetic resin body 11 and a cover plate 12 supported above the body 11. A phenolic rotor 13 is mounted between the cover plate 12 and the body 11 and is formed with an integral pivot post 14 which is received in an aperture in the cover plate 12 so as to journal the rotor 13 for angular movement relative to the body 11 and the cover plate 12 about the pivot post 14. Mounted in respective bores 15 in the rotor 13 are a pair of conductive rollers 16, each of the rollers 16 being urged into engagement with the body 11 by a helical compression spring 17 received in the respective bore 15. The rollers 16 each define a movable contact of the switch and a pair of contact blades l8, 19 (FIG. 3) received in respective apertures in the base 11 are positioned adjacent each of the rollers 16 so as to be engageable by their respective rollers during angular movement of the rotor 13. Each contact blade 18, 19 is of rectangular cross section and is arranged so that one axial end surface, indicated by the suffix a in the drawings, of the respective contact blade is positioned in the path of movement of its respective roller 16. The pairs of contact blades 18, 19 defing the fixed contacts of the switch, and rotor 13 being movable between an inoperative position in which no-circuits are made, a first operative position in which one of the rollers 16 bridges one pair of fixed contacts 18, 19 and a second operative position in which the other roller 16 bridges the other pair of fixed contacts 18, 19. Detent means (not shown) are provided for releasably retaining the rotor in its inoperative position and the first and second operative positions, and an operating lever 21 is secured to the rotor 13 and extends at one end from the rotor 13 to define means for imparting movement to the rotor in use.

The switch described above is intended for use as a direction indicator switch of a road vehicle, the switch being mounted in use on the steering column of the road vehicle with the steering column extending through apertures 22, 23 in the body 11 and the cover plate 12 respectively. When the switch is mounted on the road vehicle a bearing bush 24 carried by the steer ing column is received in the aperture 23 in the cover plate 12. The bush 24 is formed on its outside surface with an integral striker, indicated at 25, and the rotor 13 is provided with a pair of flexible, cancelling arms 26 arranged so that when the rotor 13 is moved into an operative position one of the cancelling arms 26 is moved into the path of movement of the striker 25. The operation of the cancelling arms 26 under the action of the striker 25 is entirely conventional and hence will not be described in detail. In addition, the switch includes a further set of electrical contacts 27, the operating level 21 being capable of angular movement about an axis at right angles to the rotational axis of the rotor 13 between a plurality of operative positions in which respective pairs of the contacts 27 are operated. The further set of contacts 27 would normally be arranged to control the headlamps of the vehicle.

Referring now to FIG. 3 and considering for convenience one pair of contact blades 18, 19, each blade is arranged so that one edge, indicated by the suffix b in FIG. 3, of said one axial end surface of the respective blade is inclined at an acute angle to a radius of the rotor, indicated by the dotted line 29 in the drawings, the radius 29 passing through the pivot axis of the rotor, generally indicated at 28 in the drawings, and the respective contact blade. By arranging the contactblades 18, 19 in this way, the portions of the surface of the respective roller 16 which engage the axial end surfaces 18a, 19a of the contact blades move axially along the roller 16 as the roller is moved angularly over the end surfaces 18a 19a. The arrangement of the other pair of contact blades 18, 19 is substantially the same as that described for said one pair of contact blades. Thus,

in use a relatively large area of the surface of each roller 16 engages its respective pair of contact blades 18, 19 so that wear of the rollers, due to arcing between the contacts, is spread over a similarly large area of the surface of each roller, rather than being confined to a narrow band on the surface which would be the case of the contact blades were not angled as described above.

It is to be appreciated that the evenness of wear of the rollers 16 obtained by angling the contact blades l8, 19 results in a longer useful life for the rollers 16.

In the example shown in FIG. 3, the axis of rotation of each roller 16 is arranged to be parallel with an imaginary line 31 passing through the pivot axis 28 and the center of gravity of the respective roller 16,

generally indicated at 32 in the drawings, ie each roller 16 has an axis of rotation'which lies radially with respect to the pivot axis 28. However, in a modification of this arrangement, as shown in FIG. 4, the axis of rotation of each roller 16 is inclined at an acute angle to the imaginary line 32 so that during angular movement of the respective roller 16 over its pair of contact blades 18, 19 the frictional force between the roller 16 and the blades causes the surface of the roller 16 to undergo sliding movement as well as rotational movement relative to the contact blades and hence provide a cleaning action to the contact blades.

I claim:

1. An electrical switch comprising a base, a cover extending over the base, a rotor mounted between the base and the cover for angular movement relative thereto, a conductive roller mounted in a bore in the rotor and defining the movable contact of the switch, resilient spring means also disposed in said bore for urging said roller into contact with the base, and a pair of contact blades carried by the base, each contact blade being of rectangular cross section and being arranged so that one axial end surface of the respective contact blades is positioned in the path of movement of the roller, the contact blades defining fixed contacts of the switch and the roller bridging the fixed contacts to complete a circuit therebetween in one angular position of the rotor, at least one of the contact blades being arranged so that one edge of said one axial end surface of the contact blade is inclined at an acute angle to a line extending radially from the pivot axis of t the rotor through said contact blade so that the portion of the surface of the roller which engages said one axial end surface of the contact blade moves axially along the roller as the roller is moved angularly over said :one axial end surface.

2. An electrical switch as claimed in claim 1, wherein the axis of rotation of the roller is inclined at an acute angle to an imaginary line passing through the pivot axis of the rotor so that, during angular movement of the roller over said contact blades, the surface of the roller undergoes sliding movement as well as rotational movement relative to the contact blades and hence provides a cleaning action to the contact blades.

3. An electrical switch as claimed in claim 1, wherein the axis of rotation of the roller lies radially with respect to the pivot axis of the rotor.

4. An electrical switch as claimed in claim 1, wherein an operating lever is provided for pivoting the rotor about the pivot axis, said operating lever also being capable of angular movement about an axis at right an gles to the pivot axis and wherein a further pair of contacts is provided on the body and are adapted to be operated by said angular movement of the operating lever. i 

1. An electrical switch comprising a base, a cover extending over the base, a rotor mounted between the base and the cover for angular movement relative thereto, a conductive roller mounted in a bore in the rotor and defining the movable contact of the switch, resilient spring means also disposed in said bore for urging said roller into contact with the base, and a pair of contact blades carried by the base, each contact blade being of rectangular cross section and being arranged so that one axial end surface of the respective contact blades is positioned in the path of movement of the roller, the contact blades defining fixed contacts of the switch and the roller bridging the fixed contacts to complete a circuit therebetween in one angular position of the rotor, at least one of the contact blades being arranged so that one edge of said one axial end surface of the contact blade is inclined at an acute angle to a line extending radially from the pivot axis of the rotor through said contact blade so that the portion of the surface of the roller which engages said one axial end surface of the contact blade moves axially along the roller as the roller is moved angularly over said one axial end surface.
 2. An electrical switch as claimed in claim 1, wherein the axis of rotation of the roller is inclined at an acute angle to an imaginary line passing through the pivot axis of the rotor so that, during angular movement of the roller over said contact blades, the surface of the roller undergoes sliding movement as well as rotational movement relative to the contact blades and hence provides a cleaning action to the contact blades.
 3. An electrical switch as claimed in claim 1, wherein the axis of rotation of the roller lies radially with respect to the pivot axis of the rotor.
 4. An electrical switch as claimed in claim 1, wherein an operating lever is provided for pivoting the rotor about the pivot axis, said operating lever also being capable of angular movement about an axis at right angles to the pivot axis and wherein a further pair of contacts is provided on the body and are adapted to be operated by said angular movement of the operating lever. 